diff mbox

[v4] video: add OpenCores VGA/LCD framebuffer driver

Message ID 1385739911-6541-1-git-send-email-stefan.kristiansson@saunalahti.fi (mailing list archive)
State New, archived
Headers show

Commit Message

Stefan Kristiansson Nov. 29, 2013, 3:45 p.m. UTC
This adds support for the VGA/LCD core available from OpenCores:
http://opencores.org/project,vga_lcd

The driver have been tested together with both OpenRISC and
ARM (socfpga) processors.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
---
Changes in v2:
- Add Microblaze as an example user and fix a typo in Xilinx Zynq

Changes in v3:
- Use devm_kzalloc instead of kzalloc
- Remove superflous MODULE #ifdef

Changes in v4:
- Remove 'default n' in Kconfig
- Simplify ioremap/request_mem_region by using devm_ioremap_resource
- Remove release_mem_region
---
 drivers/video/Kconfig  |  16 ++
 drivers/video/Makefile |   1 +
 drivers/video/ocfb.c   | 454 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 471 insertions(+)
 create mode 100644 drivers/video/ocfb.c

Comments

Tomi Valkeinen Jan. 10, 2014, 12:08 p.m. UTC | #1
Hi,

On 2013-11-29 17:45, Stefan Kristiansson wrote:
> This adds support for the VGA/LCD core available from OpenCores:
> http://opencores.org/project,vga_lcd
> 
> The driver have been tested together with both OpenRISC and
> ARM (socfpga) processors.
> 
> Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>

If I'm not mistaken, this driver has been designed so that there can
only be one VGA/LCD core device on the system.

It would be better to get rid of those static structs, and have the
driver data per device as it should. That way the driver works even with
multiple VGA/LCD cores (although the video mode module option is a bit
odd in that case).

 Tomi
Stefan Kristiansson Jan. 10, 2014, 4:16 p.m. UTC | #2
On Fri, Jan 10, 2014 at 02:08:27PM +0200, Tomi Valkeinen wrote:
> Hi,
> 
> On 2013-11-29 17:45, Stefan Kristiansson wrote:
> > This adds support for the VGA/LCD core available from OpenCores:
> > http://opencores.org/project,vga_lcd
> > 
> > The driver have been tested together with both OpenRISC and
> > ARM (socfpga) processors.
> > 
> > Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
> 
> If I'm not mistaken, this driver has been designed so that there can
> only be one VGA/LCD core device on the system.
> 
> It would be better to get rid of those static structs, and have the
> driver data per device as it should. That way the driver works even with
> multiple VGA/LCD cores (although the video mode module option is a bit
> odd in that case).
> 

You're right, it's a completely realistic scenario with several
VGA/LCD cores in the system, so the one device only restriction is bad.
And looking closer at the static structs, I see that the ocfb_var and ocfb_fix
doesn't surve any purpose at all, so they can just be removed.
And the information in ocfb_par can easily be obtained directly from ocfb_dev
instead, so by setting info.par to point at that, the ocfb_par struct can also
be removed completely.
Thanks, that suggestion makes the implementation cleaner as well.

I'll post an updated patch with the changes.

Stefan
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diff mbox

Patch

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 84b685f..8e41a1e 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -979,6 +979,22 @@  config FB_PVR2
 	  (<file:drivers/video/pvr2fb.c>). Please see the file
 	  <file:Documentation/fb/pvr2fb.txt>.
 
+config FB_OPENCORES
+	tristate "OpenCores VGA/LCD core 2.0 framebuffer support"
+	depends on FB
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	help
+	  This enables support for the OpenCores VGA/LCD core.
+
+	  The OpenCores VGA/LCD core is typically used together with
+	  softcore CPUs (e.g. OpenRISC or Microblaze) or hard processor
+	  systems (e.g. Altera socfpga or Xilinx Zynq) on FPGAs.
+
+	  The source code and specification for the core is available at
+	  <http://opencores.org/project,vga_lcd>
+
 config FB_S1D13XXX
 	tristate "Epson S1D13XXX framebuffer support"
 	depends on FB
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index e8bae8d..ae17ddf 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -150,6 +150,7 @@  obj-$(CONFIG_FB_NUC900)           += nuc900fb.o
 obj-$(CONFIG_FB_JZ4740)		  += jz4740_fb.o
 obj-$(CONFIG_FB_PUV3_UNIGFX)      += fb-puv3.o
 obj-$(CONFIG_FB_HYPERV)		  += hyperv_fb.o
+obj-$(CONFIG_FB_OPENCORES)	  += ocfb.o
 
 # Platform or fallback drivers go here
 obj-$(CONFIG_FB_UVESA)            += uvesafb.o
diff --git a/drivers/video/ocfb.c b/drivers/video/ocfb.c
new file mode 100644
index 0000000..51e9795
--- /dev/null
+++ b/drivers/video/ocfb.c
@@ -0,0 +1,454 @@ 
+/*
+ * OpenCores VGA/LCD 2.0 core frame buffer driver
+ *
+ * Copyright (C) 2013 Stefan Kristiansson, stefan.kristiansson@saunalahti.fi
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <linux/dma-mapping.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+
+/* OCFB register defines */
+#define OCFB_CTRL	0x000
+#define OCFB_STAT	0x004
+#define OCFB_HTIM	0x008
+#define OCFB_VTIM	0x00c
+#define OCFB_HVLEN	0x010
+#define OCFB_VBARA	0x014
+#define OCFB_PALETTE	0x800
+
+#define OCFB_CTRL_VEN	0x00000001 /* Video Enable */
+#define OCFB_CTRL_HIE	0x00000002 /* HSync Interrupt Enable */
+#define OCFB_CTRL_PC	0x00000800 /* 8-bit Pseudo Color Enable*/
+#define OCFB_CTRL_CD8	0x00000000 /* Color Depth 8 */
+#define OCFB_CTRL_CD16	0x00000200 /* Color Depth 16 */
+#define OCFB_CTRL_CD24	0x00000400 /* Color Depth 24 */
+#define OCFB_CTRL_CD32	0x00000600 /* Color Depth 32 */
+#define OCFB_CTRL_VBL1	0x00000000 /* Burst Length 1 */
+#define OCFB_CTRL_VBL2	0x00000080 /* Burst Length 2 */
+#define OCFB_CTRL_VBL4	0x00000100 /* Burst Length 4 */
+#define OCFB_CTRL_VBL8	0x00000180 /* Burst Length 8 */
+
+#define PALETTE_SIZE	256
+
+#define OCFB_NAME	"OC VGA/LCD"
+
+static char *mode_option;
+
+static const struct fb_videomode default_mode = {
+	/* 640x480 @ 60 Hz, 31.5 kHz hsync */
+	NULL, 60, 640, 480, 39721, 40, 24, 32, 11, 96, 2,
+	0, FB_VMODE_NONINTERLACED
+};
+
+struct ocfb_dev {
+	struct fb_info info;
+	void __iomem *regs;
+	/* flag indicating whether the regs are little endian accessed */
+	int little_endian;
+	/* Physical and virtual addresses of framebuffer */
+	phys_addr_t fb_phys;
+	void __iomem *fb_virt;
+	u32 pseudo_palette[PALETTE_SIZE];
+};
+
+struct ocfb_par {
+	void __iomem *pal_adr;
+};
+
+static struct ocfb_par ocfb_par_priv;
+
+static struct fb_var_screeninfo ocfb_var;
+static struct fb_fix_screeninfo ocfb_fix;
+
+#ifndef MODULE
+static int __init ocfb_setup(char *options)
+{
+	char *curr_opt;
+
+	if (!options || !*options)
+		return 0;
+
+	while ((curr_opt = strsep(&options, ",")) != NULL) {
+		if (!*curr_opt)
+			continue;
+		mode_option = curr_opt;
+	}
+
+	return 0;
+}
+#endif
+
+static inline u32 ocfb_readreg(struct ocfb_dev *fbdev, loff_t offset)
+{
+	if (fbdev->little_endian)
+		return ioread32(fbdev->regs + offset);
+	else
+		return ioread32be(fbdev->regs + offset);
+}
+
+static void ocfb_writereg(struct ocfb_dev *fbdev, loff_t offset, u32 data)
+{
+	if (fbdev->little_endian)
+		iowrite32(data, fbdev->regs + offset);
+	else
+		iowrite32be(data, fbdev->regs + offset);
+}
+
+static int ocfb_setupfb(struct ocfb_dev *fbdev)
+{
+	unsigned long bpp_config;
+	struct fb_var_screeninfo *var = &fbdev->info.var;
+	struct device *dev = fbdev->info.device;
+	u32 hlen;
+	u32 vlen;
+
+	/* Disable display */
+	ocfb_writereg(fbdev, OCFB_CTRL, 0);
+
+	/* Register framebuffer address */
+	fbdev->little_endian = 0;
+	ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys);
+
+	/* Detect endianess */
+	if (ocfb_readreg(fbdev, OCFB_VBARA) != fbdev->fb_phys) {
+		fbdev->little_endian = 1;
+		ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys);
+	}
+
+	/* Horizontal timings */
+	ocfb_writereg(fbdev, OCFB_HTIM, (var->hsync_len - 1) << 24 |
+		      (var->right_margin - 1) << 16 | (var->xres - 1));
+
+	/* Vertical timings */
+	ocfb_writereg(fbdev, OCFB_VTIM, (var->vsync_len - 1) << 24 |
+		      (var->lower_margin - 1) << 16 | (var->yres - 1));
+
+	/* Total length of frame */
+	hlen = var->left_margin + var->right_margin + var->hsync_len +
+		var->xres;
+
+	vlen = var->upper_margin + var->lower_margin + var->vsync_len +
+		var->yres;
+
+	ocfb_writereg(fbdev, OCFB_HVLEN, (hlen - 1) << 16 | (vlen - 1));
+
+	bpp_config = OCFB_CTRL_CD8;
+	switch (var->bits_per_pixel) {
+	case 8:
+		if (!var->grayscale)
+			bpp_config |= OCFB_CTRL_PC;  /* enable palette */
+		break;
+
+	case 16:
+		bpp_config |= OCFB_CTRL_CD16;
+		break;
+
+	case 24:
+		bpp_config |= OCFB_CTRL_CD24;
+		break;
+
+	case 32:
+		bpp_config |= OCFB_CTRL_CD32;
+		break;
+
+	default:
+		dev_err(dev, "no bpp specified\n");
+		break;
+	}
+
+	/* maximum (8) VBL (video memory burst length) */
+	bpp_config |= OCFB_CTRL_VBL8;
+
+	/* Enable output */
+	ocfb_writereg(fbdev, OCFB_CTRL, (OCFB_CTRL_VEN | bpp_config));
+
+	return 0;
+}
+
+static int ocfb_setcolreg(unsigned regno, unsigned red, unsigned green,
+			  unsigned blue, unsigned transp,
+			  struct fb_info *info)
+{
+	struct ocfb_par *par = (struct ocfb_par *)info->par;
+	u32 color;
+
+	if (regno >= info->cmap.len) {
+		dev_err(info->device, "regno >= cmap.len\n");
+		return 1;
+	}
+
+	if (info->var.grayscale) {
+		/* grayscale = 0.30*R + 0.59*G + 0.11*B */
+		red = green = blue = (red * 77 + green * 151 + blue * 28) >> 8;
+	}
+
+	red >>= (16 - info->var.red.length);
+	green >>= (16 - info->var.green.length);
+	blue >>= (16 - info->var.blue.length);
+	transp >>= (16 - info->var.transp.length);
+
+	if (info->var.bits_per_pixel == 8 && !info->var.grayscale) {
+		regno <<= 2;
+		color = (red << 16) | (green << 8) | blue;
+		ocfb_writereg(par->pal_adr, regno, color);
+	} else {
+		((u32 *)(info->pseudo_palette))[regno] =
+			(red << info->var.red.offset) |
+			(green << info->var.green.offset) |
+			(blue << info->var.blue.offset) |
+			(transp << info->var.transp.offset);
+	}
+
+	return 0;
+}
+
+static int ocfb_init_fix(struct ocfb_dev *fbdev)
+{
+	struct fb_var_screeninfo *var = &fbdev->info.var;
+	struct fb_fix_screeninfo *fix = &fbdev->info.fix;
+
+	strcpy(fix->id, OCFB_NAME);
+
+	fix->line_length = var->xres * var->bits_per_pixel/8;
+	fix->smem_len = fix->line_length * var->yres;
+	fix->type = FB_TYPE_PACKED_PIXELS;
+
+	if (var->bits_per_pixel == 8 && !var->grayscale)
+		fix->visual = FB_VISUAL_PSEUDOCOLOR;
+	else
+		fix->visual = FB_VISUAL_TRUECOLOR;
+
+	return 0;
+}
+
+static int ocfb_init_var(struct ocfb_dev *fbdev)
+{
+	struct fb_var_screeninfo *var = &fbdev->info.var;
+
+	var->accel_flags = FB_ACCEL_NONE;
+	var->activate = FB_ACTIVATE_NOW;
+	var->xres_virtual = var->xres;
+	var->yres_virtual = var->yres;
+
+	switch (var->bits_per_pixel) {
+	case 8:
+		var->transp.offset = 0;
+		var->transp.length = 0;
+		var->red.offset = 0;
+		var->red.length = 8;
+		var->green.offset = 0;
+		var->green.length = 8;
+		var->blue.offset = 0;
+		var->blue.length = 8;
+		break;
+
+	case 16:
+		var->transp.offset = 0;
+		var->transp.length = 0;
+		var->red.offset = 11;
+		var->red.length = 5;
+		var->green.offset = 5;
+		var->green.length = 6;
+		var->blue.offset = 0;
+		var->blue.length  = 5;
+		break;
+
+	case 24:
+		var->transp.offset = 0;
+		var->transp.length = 0;
+		var->red.offset = 16;
+		var->red.length = 8;
+		var->green.offset = 8;
+		var->green.length = 8;
+		var->blue.offset = 0;
+		var->blue.length = 8;
+		break;
+
+	case 32:
+		var->transp.offset = 24;
+		var->transp.length = 8;
+		var->red.offset = 16;
+		var->red.length = 8;
+		var->green.offset = 8;
+		var->green.length = 8;
+		var->blue.offset = 0;
+		var->blue.length = 8;
+		break;
+	}
+
+	return 0;
+}
+
+static struct fb_ops ocfb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_setcolreg	= ocfb_setcolreg,
+	.fb_fillrect	= cfb_fillrect,
+	.fb_copyarea	= cfb_copyarea,
+	.fb_imageblit	= cfb_imageblit,
+};
+
+static int ocfb_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	struct ocfb_dev *fbdev;
+	struct ocfb_par *par = &ocfb_par_priv;
+	struct resource *res;
+	int fbsize;
+
+	fbdev = devm_kzalloc(&pdev->dev, sizeof(*fbdev), GFP_KERNEL);
+	if (!fbdev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, fbdev);
+
+	fbdev->info.fbops = &ocfb_ops;
+	fbdev->info.var = ocfb_var;
+	fbdev->info.fix = ocfb_fix;
+	fbdev->info.device = &pdev->dev;
+	fbdev->info.par = par;
+
+	/* Video mode setup */
+	if (!fb_find_mode(&fbdev->info.var, &fbdev->info, mode_option,
+			  NULL, 0, &default_mode, 16)) {
+		dev_err(&pdev->dev, "No valid video modes found\n");
+		return -EINVAL;
+	}
+	ocfb_init_var(fbdev);
+	ocfb_init_fix(fbdev);
+
+	/* Request I/O resource */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "I/O resource request failed\n");
+		return -ENXIO;
+	}
+	res->flags &= ~IORESOURCE_CACHEABLE;
+	fbdev->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(fbdev->regs))
+		return PTR_ERR(fbdev->regs);
+
+	par->pal_adr = fbdev->regs + OCFB_PALETTE;
+
+	/* Allocate framebuffer memory */
+	fbsize = fbdev->info.fix.smem_len;
+	fbdev->fb_virt = dma_alloc_coherent(&pdev->dev, PAGE_ALIGN(fbsize),
+					    &fbdev->fb_phys, GFP_KERNEL);
+	if (!fbdev->fb_virt) {
+		dev_err(&pdev->dev,
+			"Frame buffer memory allocation failed\n");
+		return -ENOMEM;
+	}
+	fbdev->info.fix.smem_start = fbdev->fb_phys;
+	fbdev->info.screen_base = (void __iomem *)fbdev->fb_virt;
+	fbdev->info.pseudo_palette = fbdev->pseudo_palette;
+
+	/* Clear framebuffer */
+	memset_io((void __iomem *)fbdev->fb_virt, 0, fbsize);
+
+	/* Setup and enable the framebuffer */
+	ocfb_setupfb(fbdev);
+
+	if (fbdev->little_endian)
+		fbdev->info.flags |= FBINFO_FOREIGN_ENDIAN;
+
+	/* Allocate color map */
+	ret = fb_alloc_cmap(&fbdev->info.cmap, PALETTE_SIZE, 0);
+	if (ret) {
+		dev_err(&pdev->dev, "Color map allocation failed\n");
+		goto err_dma_free;
+	}
+
+	/* Register framebuffer */
+	ret = register_framebuffer(&fbdev->info);
+	if (ret) {
+		dev_err(&pdev->dev, "Framebuffer registration failed\n");
+		goto err_dealloc_cmap;
+	}
+
+	return 0;
+
+err_dealloc_cmap:
+	fb_dealloc_cmap(&fbdev->info.cmap);
+
+err_dma_free:
+	dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbsize), fbdev->fb_virt,
+			  fbdev->fb_phys);
+
+	return ret;
+}
+
+static int ocfb_remove(struct platform_device *pdev)
+{
+	struct ocfb_dev *fbdev = platform_get_drvdata(pdev);
+
+	unregister_framebuffer(&fbdev->info);
+	fb_dealloc_cmap(&fbdev->info.cmap);
+	dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbdev->info.fix.smem_len),
+			  fbdev->fb_virt, fbdev->fb_phys);
+
+	/* Disable display */
+	ocfb_writereg(fbdev, OCFB_CTRL, 0);
+
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct of_device_id ocfb_match[] = {
+	{ .compatible = "opencores,ocfb", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ocfb_match);
+
+static struct platform_driver ocfb_driver = {
+	.probe  = ocfb_probe,
+	.remove	= ocfb_remove,
+	.driver = {
+		.name = "ocfb_fb",
+		.of_match_table = ocfb_match,
+	}
+};
+
+/*
+ * Init and exit routines
+ */
+static int __init ocfb_init(void)
+{
+#ifndef MODULE
+	char *option = NULL;
+
+	if (fb_get_options("ocfb", &option))
+		return -ENODEV;
+	ocfb_setup(option);
+#endif
+	return platform_driver_register(&ocfb_driver);
+}
+
+static void __exit ocfb_exit(void)
+{
+	platform_driver_unregister(&ocfb_driver);
+}
+
+module_init(ocfb_init);
+module_exit(ocfb_exit);
+
+MODULE_AUTHOR("Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>");
+MODULE_DESCRIPTION("OpenCores VGA/LCD 2.0 frame buffer driver");
+MODULE_LICENSE("GPL v2");
+module_param(mode_option, charp, 0);
+MODULE_PARM_DESC(mode_option, "Video mode ('<xres>x<yres>[-<bpp>][@refresh]')");